neo-go/pkg/core/native/policy.go

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package native
import (
"encoding/binary"
"math/big"
"sort"
"sync"
"github.com/nspcc-dev/neo-go/pkg/core/dao"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/network/payload"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
"github.com/pkg/errors"
)
const (
policyName = "Policy"
policyContractID = -3
defaultMaxBlockSize = 1024 * 256
defaultMaxTransactionsPerBlock = 512
defaultFeePerByte = 1000
defaultMaxVerificationGas = 50000000
)
var (
// maxTransactionsPerBlockKey is a key used to store the maximum number of
// transactions allowed in block.
maxTransactionsPerBlockKey = []byte{23}
// feePerByteKey is a key used to store the minimum fee per byte for
// transaction.
feePerByteKey = []byte{10}
// blockedAccountsKey is a key used to store the list of blocked accounts.
blockedAccountsKey = []byte{15}
// maxBlockSizeKey is a key used to store the maximum block size value.
maxBlockSizeKey = []byte{16}
)
// Policy represents Policy native contract.
type Policy struct {
interop.ContractMD
lock sync.RWMutex
// isValid defies whether cached values were changed during the current
// consensus iteration. If false, these values will be updated after
// blockchain DAO persisting. If true, we can safely use cached values.
isValid bool
maxTransactionsPerBlock uint32
maxBlockSize uint32
feePerByte int64
maxVerificationGas int64
}
var _ interop.Contract = (*Policy)(nil)
// newPolicy returns Policy native contract.
func newPolicy() *Policy {
p := &Policy{ContractMD: *interop.NewContractMD(policyName)}
p.ContractID = policyContractID
p.Manifest.Features |= smartcontract.HasStorage
desc := newDescriptor("getMaxTransactionsPerBlock", smartcontract.IntegerType)
md := newMethodAndPrice(p.getMaxTransactionsPerBlock, 1000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, true)
desc = newDescriptor("getMaxBlockSize", smartcontract.IntegerType)
md = newMethodAndPrice(p.getMaxBlockSize, 1000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, true)
desc = newDescriptor("getFeePerByte", smartcontract.IntegerType)
md = newMethodAndPrice(p.getFeePerByte, 1000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, true)
desc = newDescriptor("getBlockedAccounts", smartcontract.ArrayType)
md = newMethodAndPrice(p.getBlockedAccounts, 1000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, true)
desc = newDescriptor("setMaxBlockSize", smartcontract.BoolType,
manifest.NewParameter("value", smartcontract.IntegerType))
md = newMethodAndPrice(p.setMaxBlockSize, 3000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, false)
desc = newDescriptor("setMaxTransactionsPerBlock", smartcontract.BoolType,
manifest.NewParameter("value", smartcontract.IntegerType))
md = newMethodAndPrice(p.setMaxTransactionsPerBlock, 3000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, false)
desc = newDescriptor("setFeePerByte", smartcontract.BoolType,
manifest.NewParameter("value", smartcontract.IntegerType))
md = newMethodAndPrice(p.setFeePerByte, 3000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, false)
desc = newDescriptor("blockAccount", smartcontract.BoolType,
manifest.NewParameter("account", smartcontract.Hash160Type))
md = newMethodAndPrice(p.blockAccount, 3000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, false)
desc = newDescriptor("unblockAccount", smartcontract.BoolType,
manifest.NewParameter("account", smartcontract.Hash160Type))
md = newMethodAndPrice(p.unblockAccount, 3000000, smartcontract.NoneFlag)
p.AddMethod(md, desc, false)
desc = newDescriptor("onPersist", smartcontract.VoidType)
md = newMethodAndPrice(getOnPersistWrapper(p.OnPersist), 0, smartcontract.AllowModifyStates)
p.AddMethod(md, desc, false)
return p
}
// Metadata implements Contract interface.
func (p *Policy) Metadata() *interop.ContractMD {
return &p.ContractMD
}
// Initialize initializes Policy native contract and implements Contract interface.
func (p *Policy) Initialize(ic *interop.Context) error {
si := &state.StorageItem{
Value: make([]byte, 4, 8),
}
binary.LittleEndian.PutUint32(si.Value, defaultMaxBlockSize)
err := ic.DAO.PutStorageItem(p.ContractID, maxBlockSizeKey, si)
if err != nil {
return err
}
binary.LittleEndian.PutUint32(si.Value, defaultMaxTransactionsPerBlock)
err = ic.DAO.PutStorageItem(p.ContractID, maxTransactionsPerBlockKey, si)
if err != nil {
return err
}
si.Value = si.Value[:8]
binary.LittleEndian.PutUint64(si.Value, defaultFeePerByte)
err = ic.DAO.PutStorageItem(p.ContractID, feePerByteKey, si)
if err != nil {
return err
}
ba := new(BlockedAccounts)
si.Value = ba.Bytes()
err = ic.DAO.PutStorageItem(p.ContractID, blockedAccountsKey, si)
if err != nil {
return err
}
p.isValid = true
p.maxTransactionsPerBlock = defaultMaxTransactionsPerBlock
p.maxBlockSize = defaultMaxBlockSize
p.feePerByte = defaultFeePerByte
p.maxVerificationGas = defaultMaxVerificationGas
return nil
}
// OnPersist implements Contract interface.
func (p *Policy) OnPersist(ic *interop.Context) error {
return nil
}
// OnPersistEnd updates cached Policy values if they've been changed
func (p *Policy) OnPersistEnd(dao dao.DAO) {
if p.isValid {
return
}
p.lock.Lock()
defer p.lock.Unlock()
maxTxPerBlock := p.getUint32WithKey(dao, maxTransactionsPerBlockKey)
p.maxTransactionsPerBlock = maxTxPerBlock
maxBlockSize := p.getUint32WithKey(dao, maxBlockSizeKey)
p.maxBlockSize = maxBlockSize
feePerByte := p.getInt64WithKey(dao, feePerByteKey)
p.feePerByte = feePerByte
p.isValid = true
}
// getMaxTransactionsPerBlock is Policy contract method and returns the upper
// limit of transactions per block.
func (p *Policy) getMaxTransactionsPerBlock(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
return stackitem.NewBigInteger(big.NewInt(int64(p.GetMaxTransactionsPerBlockInternal(ic.DAO))))
}
// GetMaxTransactionsPerBlockInternal returns the upper limit of transactions per
// block.
func (p *Policy) GetMaxTransactionsPerBlockInternal(dao dao.DAO) uint32 {
p.lock.RLock()
defer p.lock.RUnlock()
if p.isValid {
return p.maxTransactionsPerBlock
}
return p.getUint32WithKey(dao, maxTransactionsPerBlockKey)
}
// getMaxBlockSize is Policy contract method and returns maximum block size.
func (p *Policy) getMaxBlockSize(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
p.lock.RLock()
defer p.lock.RUnlock()
if p.isValid {
return stackitem.NewBigInteger(big.NewInt(int64(p.maxBlockSize)))
}
return stackitem.NewBigInteger(big.NewInt(int64(p.getUint32WithKey(ic.DAO, maxBlockSizeKey))))
}
// getFeePerByte is Policy contract method and returns required transaction's fee
// per byte.
func (p *Policy) getFeePerByte(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
return stackitem.NewBigInteger(big.NewInt(p.GetFeePerByteInternal(ic.DAO)))
}
// GetFeePerByteInternal returns required transaction's fee per byte.
func (p *Policy) GetFeePerByteInternal(dao dao.DAO) int64 {
p.lock.RLock()
defer p.lock.RUnlock()
if p.isValid {
return p.feePerByte
}
return p.getInt64WithKey(dao, feePerByteKey)
}
// GetMaxVerificationGas returns maximum gas allowed to be burned during verificaion.
func (p *Policy) GetMaxVerificationGas(_ dao.DAO) int64 {
return p.maxVerificationGas
}
// getBlockedAccounts is Policy contract method and returns list of blocked
// accounts hashes.
func (p *Policy) getBlockedAccounts(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
ba, err := p.GetBlockedAccountsInternal(ic.DAO)
if err != nil {
panic(err)
}
return ba.ToStackItem()
}
// GetBlockedAccountsInternal returns list of blocked accounts hashes.
func (p *Policy) GetBlockedAccountsInternal(dao dao.DAO) (BlockedAccounts, error) {
si := dao.GetStorageItem(p.ContractID, blockedAccountsKey)
if si == nil {
return nil, errors.New("BlockedAccounts uninitialized")
}
ba, err := BlockedAccountsFromBytes(si.Value)
if err != nil {
return nil, err
}
return ba, nil
}
// setMaxTransactionsPerBlock is Policy contract method and sets the upper limit
// of transactions per block.
func (p *Policy) setMaxTransactionsPerBlock(ic *interop.Context, args []stackitem.Item) stackitem.Item {
ok, err := p.checkValidators(ic)
if err != nil {
panic(err)
}
if !ok {
return stackitem.NewBool(false)
}
value := uint32(toBigInt(args[0]).Int64())
p.lock.Lock()
defer p.lock.Unlock()
err = p.setUint32WithKey(ic.DAO, maxTransactionsPerBlockKey, value)
if err != nil {
panic(err)
}
p.isValid = false
return stackitem.NewBool(true)
}
// setMaxBlockSize is Policy contract method and sets maximum block size.
func (p *Policy) setMaxBlockSize(ic *interop.Context, args []stackitem.Item) stackitem.Item {
ok, err := p.checkValidators(ic)
if err != nil {
panic(err)
}
if !ok {
return stackitem.NewBool(false)
}
value := uint32(toBigInt(args[0]).Int64())
if payload.MaxSize <= value {
return stackitem.NewBool(false)
}
p.lock.Lock()
defer p.lock.Unlock()
err = p.setUint32WithKey(ic.DAO, maxBlockSizeKey, value)
if err != nil {
panic(err)
}
p.isValid = false
return stackitem.NewBool(true)
}
// setFeePerByte is Policy contract method and sets transaction's fee per byte.
func (p *Policy) setFeePerByte(ic *interop.Context, args []stackitem.Item) stackitem.Item {
ok, err := p.checkValidators(ic)
if err != nil {
panic(err)
}
if !ok {
return stackitem.NewBool(false)
}
value := toBigInt(args[0]).Int64()
p.lock.Lock()
defer p.lock.Unlock()
err = p.setInt64WithKey(ic.DAO, feePerByteKey, value)
if err != nil {
panic(err)
}
p.isValid = false
return stackitem.NewBool(true)
}
// blockAccount is Policy contract method and adds given account hash to the list
// of blocked accounts.
func (p *Policy) blockAccount(ic *interop.Context, args []stackitem.Item) stackitem.Item {
ok, err := p.checkValidators(ic)
if err != nil {
panic(err)
}
if !ok {
return stackitem.NewBool(false)
}
value := toUint160(args[0])
si := ic.DAO.GetStorageItem(p.ContractID, blockedAccountsKey)
if si == nil {
panic("BlockedAccounts uninitialized")
}
ba, err := BlockedAccountsFromBytes(si.Value)
if err != nil {
panic(err)
}
indexToInsert := sort.Search(len(ba), func(i int) bool {
return !ba[i].Less(value)
})
ba = append(ba, value)
if indexToInsert != len(ba)-1 && ba[indexToInsert].Equals(value) {
return stackitem.NewBool(false)
}
if len(ba) > 1 {
copy(ba[indexToInsert+1:], ba[indexToInsert:])
ba[indexToInsert] = value
}
err = ic.DAO.PutStorageItem(p.ContractID, blockedAccountsKey, &state.StorageItem{
Value: ba.Bytes(),
})
if err != nil {
panic(err)
}
return stackitem.NewBool(true)
}
// unblockAccount is Policy contract method and removes given account hash from
// the list of blocked accounts.
func (p *Policy) unblockAccount(ic *interop.Context, args []stackitem.Item) stackitem.Item {
ok, err := p.checkValidators(ic)
if err != nil {
panic(err)
}
if !ok {
return stackitem.NewBool(false)
}
value := toUint160(args[0])
si := ic.DAO.GetStorageItem(p.ContractID, blockedAccountsKey)
if si == nil {
panic("BlockedAccounts uninitialized")
}
ba, err := BlockedAccountsFromBytes(si.Value)
if err != nil {
panic(err)
}
indexToRemove := sort.Search(len(ba), func(i int) bool {
return !ba[i].Less(value)
})
if indexToRemove == len(ba) || !ba[indexToRemove].Equals(value) {
return stackitem.NewBool(false)
}
ba = append(ba[:indexToRemove], ba[indexToRemove+1:]...)
err = ic.DAO.PutStorageItem(p.ContractID, blockedAccountsKey, &state.StorageItem{
Value: ba.Bytes(),
})
if err != nil {
panic(err)
}
return stackitem.NewBool(true)
}
func (p *Policy) getUint32WithKey(dao dao.DAO, key []byte) uint32 {
si := dao.GetStorageItem(p.ContractID, key)
if si == nil {
return 0
}
return binary.LittleEndian.Uint32(si.Value)
}
func (p *Policy) setUint32WithKey(dao dao.DAO, key []byte, value uint32) error {
si := dao.GetStorageItem(p.ContractID, key)
binary.LittleEndian.PutUint32(si.Value, value)
err := dao.PutStorageItem(p.ContractID, key, si)
if err != nil {
return err
}
return nil
}
func (p *Policy) getInt64WithKey(dao dao.DAO, key []byte) int64 {
si := dao.GetStorageItem(p.ContractID, key)
if si == nil {
return 0
}
return int64(binary.LittleEndian.Uint64(si.Value))
}
func (p *Policy) setInt64WithKey(dao dao.DAO, key []byte, value int64) error {
si := dao.GetStorageItem(p.ContractID, key)
binary.LittleEndian.PutUint64(si.Value, uint64(value))
err := dao.PutStorageItem(p.ContractID, key, si)
if err != nil {
return err
}
return nil
}
func (p *Policy) checkValidators(ic *interop.Context) (bool, error) {
prevBlock, err := ic.Chain.GetBlock(ic.Block.PrevHash)
if err != nil {
return false, err
}
return runtime.CheckHashedWitness(ic, prevBlock.NextConsensus)
}
// CheckPolicy checks whether transaction's script hashes for verifying are
// included into blocked accounts list.
func (p *Policy) CheckPolicy(ic *interop.Context, tx *transaction.Transaction) (bool, error) {
ba, err := p.GetBlockedAccountsInternal(ic.DAO)
if err != nil {
return false, err
}
scriptHashes, err := ic.Chain.GetScriptHashesForVerifying(tx)
if err != nil {
return false, err
}
for _, acc := range ba {
for _, hash := range scriptHashes {
if acc.Equals(hash) {
return false, nil
}
}
}
return true, nil
}